Particulate transfer control device

Claim 2

A control means for use with apparatus for pneumatic transfer of a particulate material of the type including an air directing portion having an air flow-way therethrough, means supplying said air flow-way with compressed air, and a particulate directing portion having a particulate flow-way therethrough communicating with said air flow-way to deposit said particulate material in said air flow-way, said control means comprisIng: air flow-way closure means operative to open and close said air flow-way; particulate flow-way closure means operative to open and close said particulate flow-way; and a sequencing mechanism operatively connected to said air flowway closure means and to said particulate flow-way closure means and having control fluid passageways and including means responsive to a first flow pattern of said control fluid in said control fluid passageways, when said air flow-way closure means and said particulate flow-way closure means are both open, to cause closing of said particulate flow-way by said particulate flow-way closure means first, followed by closing of said air flow-way by said air flow-way closure means; and means for selectively causing said control fluid to flow in said first pattern.

Claim 3

Control means according to claim 1 wherein said sequencing mechanism includes means responsive to a second flow pattern of said control fluid in said control fluid passageways when said closure means are both closed to cause opening of said air flow-way by said air flow-way closure means first, followed by opening of said particulate flow-way by said particulate flow-way closure means, said control means further comprising means for selectively causing said control fluid to flow in said second pattern.

Claim 4

Control means according to claim 2 wherein said means responsive to said first flow pattern is further operative to cause the closing of said air flow-way to proceed at a slower rate than the closing of said particulate flow-way and wherein said means responsive to said second flow pattern is further operative to cause the opening of said particulate flow-way to proceed at a slower rate than the opening of said air flow-way.

Claim 5

Control means according to claim 1 wherein said air flow-way closure means includes an air flow-way closure operator having first and second sides and movable in response to pressure on said first side thereof greater than pressure on the second side thereof to cause closing of said air flow-way; wherein said particulate flow-way closure means includes a particulate flow-way closure operator having first and second sides and movable in response to pressure on said first side thereof greater than pressure on said second side thereof to cause closing of said particulate; and wherein said sequencing mechanism has therein: a main control fluid passageway, an inlet for delivering said control fluid to said main control fluid passageway, an air closure passageway connecting said main control fluid passageway with a first area on said first side of said air flow-way closure operator, a one-way valve in said air closure passageway operative by pressure in said main control fluid passageway greater than the pressure in said first area to close said air closure passageway, a first bleed hole of smaller diameter than said main control fluid passageway connecting said main control fluid passageway to said first area, and a particulate closure passageway of greater diameter than said bleed hole connecting said main control fluid passageway with a second area on said one side of said particulate passageway closure operator.

Claim 6

Control means according to claim 4 wherein said sequencing mechanism further includes a one-way valve in said particulate closure passageway operative by pressure in said second area greater than the pressure in said main control fluid passageway to close said particulate closure passageway, and has therein a second bleed hole of smaller diameter than said main control fluid passageway connecting said particulate closure passageway to said main control fluid passageway.

Claim 7

Control means according to claim 1 wherein said control fluid is comprised of compressed air from said supplying means, and wherein said control means includes means for selectively injecting compressed air from said supplying means into the control fluid passageways of said sequencing mechanism.

Claim 8

Control means according to claim 1 wherein said pneumatic transfer apparatus is abrasive blasting apparatus and said particulate material is abrasive.